1. Field of the Disclosure
The application relates to a motor assisted rotating wheel mechanism, and, more particularly, to a motor assisted rotating wheel mechanism with an axial magnetic flux.
2. Background
Most of common motor bicycles are installed with their own auxiliary motor on the axle of front or rear wheel, and there are also motor bicycles with an auxiliary motor installed on the center of the frame body, that is, on the crank axle of the pedals.
Installing the auxiliary motor on the center of the frame body is known as a mid-motor motor bicycle, because the mid-motor motor bicycle can transmit the output power to a chain wheel on the crank axle. Compared to the motor bicycle installed with the auxiliary motor on the front or rear wheel, the mid-motor motor bicycle is more directly and suitably matched with exertion of user. Current mid-motor motor bicycles, as disclosed in U.S. Pat. No. 6,296,072, TW Patent No. I308892, TW Patent No. I265896, TW Patent No. I264399, and TW Patent No. I296596, employ the auxiliary motor with a radial magnetic flux design where the electromagnetic field generated by the auxiliary motor is perpendicular to the center of rotating axle.
The patents mentioned above have issues related to a trade-off between the volume and the twisting force. Specifically, when a larger output of twisting force is required, the auxiliary motor with motor design of radial magnetic flux has a wider size, and wider size means that a bicycle designer needs to reserve a larger space for installing the auxiliary motor. Accordingly, the appearance design of a motor bicycle is impeded and the product development of a motor bicycle is adversely affected. On the other hand, reducing the width of the auxiliary motor with a radial magnetic flux design for designing desired appearance of bicycle would, however, correspondingly reduce the output of the twisting force, and related decelerating gear set is also necessary for motor bicycle designer to increase the output of twisting force. Equipping additional decelerating gear set results in the increase of the total cost of the motor bicycle and complexity of equipment would raise.